Creutzfeldt-Jakob Disease and Bovine Spongiform Encephalopathy are transmissible, neurodegenerative and fatal prion diseases of humans and cattle, respectively. There are no commercially available, completely reliable diagnostic tests for use before the onset of symptoms. The only reliable tests in use are performed post mortem or via brain biopsy and involve histological examination. For these reasons, there is a great need for better diagnostics for these prion diseases. This application proposes to develop a rapid, extremely sensitive diagnostic test for prion based on the CANARY biosensor technology developed at MIT and an antibody that specifically recognizes the scrapie form of the prion protein in cattle and humans. The CANARY technology is composed of B-lymphocytes that have been genetically engineered to express an antibody of interest on the cell surface and calcium sensitive protein in the cell's cytosol. The interaction of the antigen with the membrane bound antibody cause the engineered biosensors to emit light, which is detectable by a small, portable luminometer. This approach allows specific testing of analytes at previously unachievable levels of speed and sensitivity. The specific tasks for Phase I include: 1) Obtaining sequences of the light and heavy chains of the variable region of the anti-prion monoclonal antibody by RT-PCR. 2) Construction of these sequences into a well characterized two vector antibody expression system. 3) Generation of a stable cell line that expresses the recombinant antibody on its surface and a calcium sensitive bioluminescent protein in the cell's cytosol that responds to the prion antibody epitope.